Lightproofed dental radiographic film developer

ABSTRACT

A small X-ray film developer has a lightproof housing having a door through which a plurality of exposed films in their lightproof wrappers may be introduced by sliding the wrapper flaps over the thin edge of a plate adapted to slide toward and away from an identification card holder which is adapted to be rotated and to be raised and lowered. After the card and films have been introduced the door is closed and a rod under the flaps is rotated about 135* around the plate to open the wrapper flaps exposing a small portion of each film so that each may be contacted by gummy portions on the card when it is turned. The plate is then slid away from the card thus withdrawing the films and the card is turned and lowered dipping the films into a developing tank. Valves controlling sources of developer, fixer and water are then operated to supply the tank successively therewith. The card is then raised and a fan is turned on to dry the developed films. The door is then opened and the card with attached developed films is removed. A film cover with appropriate windows for the films is then attached to the card leaving its identifying inscriptions and the films readable.

United States Patent [191 Perl LIGHTPROOFED DENTAL RADIOGRAPHIC FILM DEVELOPER [76] Inventor: Theodore Perl, 58 Ely Drive,

Fayetteville, NY. 13066 [22] Filed: July 20, 1971 [21] Appl. No.: 164,270

Primary Examiner-John M. Horan Assistant Examiner-Fred L. Braun Attorney-Bruns & Jenney [451 Apr. 17, 1973 ABSTRACT A small X-ray film developer has a lightproof housing having a door through which a plurality of exposed films in their lightproof wrappers may be introduced by sliding the wrapper flaps over the thin edge of a plate adapted to slide toward and away from an identification card holder which is adapted to be rotated and to be raised and lowered. After the card and films have been introduced the door is closed and a rod under the flaps is rotated about 135 around the plate to open the wrapper flaps exposing a small portion of each film so that each may be contacted by gummy portions on the card when it is turned. The plate is then slid away from the card thus withdrawing the films and the card is turned and lowered dipping the films into a developing tank. Valves controlling sources of developer, fixer and water are then operated to supply the tank successively therewith. The card is then raised and a fan is turned on to dry the developed films. The door is then opened and the card with attached developed films is removed. A film cover with appropriate windows for the films is then attached to the card leaving its identifying inscriptions and the films readable.

5 Claims, 12 Drawing Figures Patented April 17, 1973 I 3,72 7,533

5 Sheets-Sheet l INVENTOR.

THEODORE PERL BY BM QM ATTORNEYS Patented April 17, 1973 .5 Sheets-Sheet 2 N OE INVENTOR. THEODORE PERL ATTORNEYS Patented April 17, 1973 3,727,533

5 Sheets-Sheet 3 THEODORE PERL ATTORNEYS Q l N VE \ITOR LL 1 Patented April 17, 1973 5 Sheets-Sheet 4.

THEODORE PERL ATTORNEYS Patented April '17, 1973 5 Sheets-Sheet 5 E f a A Ow MP INVENTOR. THEODORE PERL ATTORNEYS LIGHTPROOFED DENTAL RADIOGlRAPHIC FILM DEVELOPER BACKGROUND OF THE INVENTION wrapper, but also with a moisture proof wrapper. The

technician charged with developing the film must first remove the moisture proof wrapping and then, in a darkroom, remove the inner lightproof wrapper and develop the film. This is time consuming and, since as many as eighteen films for a single patient may be taken of the individual teeth or pairs of teeth, including bite wing X-rays, it involves problems of identifying the individual films.

The lightproof wrapper must remain on each film until it is removed to a lightproofed location so that, in a processor having a lightproof housing, the wrapper must not be opened until the door to the housing is closed. There is, therefore, the problem of opening the wrapper mechanically and removing the film.

There is another problem in lightproofed processor apparatus in that the technician cannot see the film in its developer so that the time for developing must be precisely timed. In ordinary processors the same supply of developer is used over and over until it loses its strength, the time that the film must be left in the developer becoming longer and longer as its concentration becomes weaker.

SUMMARY OF THE INVENTION This invention contemplates providing each film with a lightproof wrapper having a flap which folds over one edge of the film but which may be mechanically folded back to uncover a portion of the film adapting it to be contacted by a member having a gummy adhesive portion adapted to become secured to the film.

A plurality of wrappers, with the flaps unopened, are inserted on a wrapper-holding, extractor slide inside a lightproof housing through an access door. A card, having information as to patient and location of the teeth filmed, is also inserted in a film carrier through this door which is then closed. The card bears the gummy adhesive for the films in the wrappers.

An arm, outside the housing, is turned to fold the flaps of all the wrappers back uncovering a portion of each film. A second arm, outside the housing, is then turned about 135 to turn the film carrier so that the adhesive coated portions of the card contact the exposed portions of the films. Another arm, outside the housing, is then turned to move the wrapper holder slide away from the card and thus to withdraw the wrappers from the films.

The second arm is then turned about 45 more, carrying the films pendant from the carrier and a fourth arm is turned carrying the card holding portion of the film carrier downward.

Below the film carrier, a developing tank is adapted to receive the lowered films, the tank being very small and this so that only small amounts of developer and fixer are used for each developing operation, the solutions, once used, being allowed to drain away without reuse. Storage tanks are provided for developer and fixer and a source of warm water for rinsing is led through a coil which heats smaller self filling tanks for the developer and fixer, the smaller tanks containing just enough solution to fill the developing tank. Valve means, accessible from outside the housing, are provided to fill the developing tank. first with developer, then water, then fixer and finally water again for rinsing.

After the films are developed the fourth arm is then turned in the opposite direction for raising the films between two rubber rollers spring biased together to wipe the films. A fan above the developing tank then dries the raised films.

After the films are dried the access door is again opened and the identification card with films still attached is removed. A folding film cover with windows on either side for the films is then attached to the card leaving the identification indicia and films available for inspection.

Motor means may be provided for turning the four levers, electrically or fluidics-operated valves may be provided for supplying the fluids to the developing tanks and an electrically or fiuidics-operated programmer may be provided for initiating and timing all operations.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view ofa machine embodying the invention, a portion of the access door being cut away;

FIG. 2 is a front view thereof, the front ofthe housing being removed for clarity;

FIG. 3 is an enlarged, fragmentary sectional view on the line 3-3 of FIG. 2;

FIG. 4 is a plan view of a film and its wrapper partially unfolded;

FIG. 5 is a fragmentary sectional view on the line 5 5 of FIG. 2, showing a portion of the machine ready for loading;

FIG. 6 is a fragmentary sectional view on the line 6- 6 of FIG. 2, showing a portion of the machine just prior to extraction of the films from their wrapper;

FIG. 7 is a fragmentary sectional view like FIG. 6 on the line 6-6 of FIG. 2, showing the extractor slide retracted and the films ready for lowering to the developing tank;

FIG. 8 is a sectional view on the line 8-8 of FIG. 2;

FIG. 9 is a sectional view showing the portions of the machine shown in FIG. 7 as viewed from the right;

FIG. 10 is a rear elevational view of the machine of FIG. 1;

FIG. 11 is an enlarged sectional view on the line 11- i1 ofFIG. 10; and

FIG. 12 is a plan view of developed films attached to an identification card and a protective cover for the films.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, a machine 10 has a lightproof housing 11 equipped with a door 12, hinged at 13 for access to the interior. At one side, the housing 11 has four crank arms l4, l5, l6 and 17, each equipped with appropriate manually graspable pins or handles and suitable stop pins, as shown.

Arm 14 operates a wrapper-opening rod, hereinafter described, carried on pulleys 18. Arm 15 rotates a shaft 19 carrying a film carrier assembly 20. Arm 16 rotates a shaft 21 carrying disks 22 at either end inside the housing which are connected by means of crank pins 23 and connecting rods 24 to advance and retract an extractor slide 25 which carries the pulleys 18. Arm 17 operates mechanism, hereinafter described, to lower portions of the film carrier.

Referring to FIG. 4, each film 26, is provided with a lightproof wrapper 27 to adapt it for developing it in machine 10. The wrapper 27 is made in'three panels 28, 29, and 30 divided by fold lines 31 and 32, the panel 28 having transversely projecting wing flaps 33 33, shown folded in over the film 26. The panel 29 normally covers the surface of the film over which the flaps 33-33 lie and the flaps 33-33 are cut back, as shown, to leave uncovered a portion of film 26 along the forward end edge of the wrapper when panel 29 is not folded over the wing flaps. Panel 30 is the cover flap, lying over the panel 28 when the wrapper is folded so that film 26 is not uncovered until the wrapper is unfolded past the fold line 32.

In loading the films in their wrappers in the machine, cover 12 is opened and the films and wrappers are inserted in a narrow slot formed'by a wrapper holder plate 35 secured in spaced relation to the slide 25 as best seen in FIG. 3. In placing the film and wrapper below plate 35, the technician allows the outer flap 30 to open slightly and overlie the slanted end 36 of slide 25, as shown at 30 in FIG. 3.

Pulleys 18 have stub shafts 37 rotatably carried in bearing blocks 38a secured to slide 25 at either side of the slide and the cover-flap-opening rod 38 extends across from one pulley 18 to the other. Rod 38 normally lies in a groove 39 extending across the slanted edge 36 so that the cover flap 30 overlies the rod, as shown at 38 at FIG. 3.

Pulleys 18 are rotated by the crank arm 14, FIG. 2, which turns the shaft 40 and pulley 41 fixed to the shaft. A pulley supporting bar 42 is freely journalled on the shaft 40 and rotatably carries the pulleys 43 and 44 fixed to their common shaft 45. A first endless belt 46, preferably a timing belt, operatively connects pulleys 41 and 43 and a second timing belt 47 connects pulleys 44 and one of the pulleys 18, the other pulley 18 turning therewith since they are connected by rod 38. Belts 46 and 47 extend in directions substantially 90 from one another, bar 42 being always substantially normal to the slide 25. Belt 47 is kept taut by a compression spring 48 extending from slide 25 to the end of bar 42, as best seen in FIG. 8.

As best seen in full lines in FIG. 3, when the arm 14 is operated, the flap-opening rod 38 travels in an approximately 135 arc and carries the flap or panel 30 with it, turning the flap and a portion of panel 29 back and uncovering a portion of the upper side of film 26 (see FIG. 4).

The film carrier 20, secured to shaft 19 and rotatable approximately 180 by turning arm 15, is made essentially in three parts: guideway members 50 at either side which are keyed to shaft 19, a plate member 51 which is slideable in the guideways of the members 50, and a holder assembly 52 comprising two transversely extending bars 53 and 54 (FIGS. 5 and 7) which are secured together slightly spaced to form a card-receiving slot therebetween for an identification card 55.

Plate 51 has a pair of stop pins 56 which are normally biased against shaft 19 by a pair of springs 57 at the sides of the plate secured at one end to the guideway members 50 and at the other ends to pins 58 projecting from the plate.

The holder 52 is slideable with respect to plate 51, bar 53 being slideable in contact with plate 51 between the guideway members 50, and bar 54 being slideable in contact with the members 50. Springs 59, on either side of plate member 51, extend from the pins 58 on the plate to studs 60 projecting from bar 53. The studs 60 are normally biased by springs 59 against a shoulder at either side of plate 51. Stop pins 61 for the card 55 project from member 53 and spring legs 62 (FIG. 2) from a spring wire secured to the front of bar 54 project through appropriate holes in the bar for securing the card in its slot.

Card 55 has its upper edge, as shown in FIG. 2, divided into segments, only three being shown, of appropriate length for contacting the exposed portions of the films 26 carried on the extractor slide 25. These portions are coated with a gunny adhesive at 63 for adhering to the films when the film carrier 20 is turned approximately by the arm 15, the slide being positioned adjacent the film carrier 20 so that the turning of the carrier is stopped by the portions at 63 coming in contact with the uncovered portions of the films.

It will be understood that the film holder 52, the extractor 25, and the width of the machine 10 may be of any desired transverse dimension in order to provide for as many films 26 as desired. Customarily X-rays ofa patients 28 teeth provide for two side views of each side and three front views for each jaw, plus four bite views. Preferably, therefore, the machine 10 should be either wide enough to develop 18 films 26 at one time or seven films at a time. It will also be noted that the films may be wrapped so that the card-contacted edge may be a long edge or a short edge and the films may vary in width so long as a system is employed which uses the same size and disposition of the film for each patient with the cards 55 arranged according to this system.

After the film carrier is turned and the adhesive at 63 is brought in contact with the films, the arm 16 is turned to move the wrapper-carrying extractor slide 25 away from the film carrier 20. As described above, when shaft 21 is turned the slide 25 is withdrawn from the position shown in FIGS. 5 and 6 to a more remote position, shown in FIG. 7, carrying the wrappers 27 away from the films 26. Arm 15 is then turned approximately 45 to complete a half revolution ofshaft 19 and the carrier 20 is disposed so as to support the films pendantly, as shown in FIG. 7, immediately above a developing tank 65.

Referring to FIG. 2, the bar 54, which is longer than bar 53, carries at either end a transversely extending pin 66 which, when the carrier 20 is inverted, enters a slot in a slotted projection 67 carried on an elongated slide 68 guided by vertically disposed ways 69 provided on the interior wall of the sides of housing 1 1. Referring to FIG. 9, arm 17, when turned, rotates a transversely extending shaft 21' to which are secured crank-disks 22' each having one end of a connecting rod 24' pivotally secured thereto at 33', the other end of the rod being pivotally secured to slide 69 exactly like the linkage 21-25 described above in connection with the extractor slide 25.

When the pins 66 are pulled down by the projections 67 on slides 68, the card holder 52 is pulled down extending the springs 59 until the bar 53 contacts the rearwardly projecting end of plate 51, as shown in FIG. 7. Plate 51 is then pulled down extending spring 57 until the end of plate 51 meets a pair of rubber rollers 70 above the tank 65.

Tank 65 is supported on a cross member 71 between the sides of the housing 11. End plates 72 extend rearward from the cross member forming in part the end walls of an overflow tank 73 which surrounds the tank 65. Tank 73 has an overflow tube 74 (FIG. 5) leading from the tank at the bottom of one end to any suitable drain outside the housing. Tank 65 is spaced from and supported by the walls of tank 73 by suitable spacing blocks 75. Tank 65 is shorter than tank 73 and narrower, being only oflittle greater thickness than film 26 and ofa depth only sufficient to accommodate the films introduced therein so that only a minimal amount of developing fluid is needed to fill it, the amount being on the order of l fluid ounce.

Referring to FIG. 6, roller 70 has its shaft rotatably carried in a bracket 76 fixed to each end plate 72. The brackets 77, which rotatably carry the ends of the shaft of roller 7012, are pivotally secured to the end plates 72 and a spring 78 biases roller 70b against roller 700 so that films 76 are easily introduced down into tank 65 between the rollers and, when the films are withdrawn, they are wiped of fluid by the rollers.

The developing tank 65 has a combination intakedrain tube 80 (FIGS. 6 and 7) leading up through, and sealed from, tank 73 and opening into the center of the bottom of the tank. At the end of tube 80 a shutoff valve 81 may be closed to shut off a drain tube 82. Above the valve 81, tube 80 is connected to a tube 83 (FIG. connecting the tank 65 tosources of fluid through valves 84, 85 and 86.

At the rear of housing 11, above the tank 65, are tanks 87 and 88 which are storage tanks for solutions of developer and fixer, respectively. The tanks 87 and 88 may have suitable covers so as to be lightproof. Below the tanks 87 and 88 are smaller tanks 89 and 90, each vented by a pipe 87' or 88' and are ofa size to precisely fill the developing tank 65. Below the tanks 89 and 90 is a plate 91 having a serpentine passage 92 for the flow of water therethrough, as best seen in FIG. 11. At one end the serpentine passage 92 is continuously supplied with water through pipe 93 (FIG. 10) from a source of heated water, not shown. At its other end the passage 92 is connected through valve 86 with the-pipe 83. When water is drawn through passage 92 it heats the fluids in tanks 89 and 90.

Referring to FIG. 11, the communication between tank 88, tank 90 and valve 85 is shown, a similar arrangement being provided for tank 87, tank 89 and valve 84. When valve 85 is operated a passage 94 connects tank 90 with pipe 83. When valve 85 is shut off, passage 94 is connected with a passage 95 connected to tank 88. In operation, of course, valve 84 is opened, tank 89 is drained filling tank 65 with warmed developer solution. When valve 84 is closed, tank 89 is connected to its supply tank 87 allowing the small tank 89 to fill with solution which will be warmed during the rinsing operation by the flow of water through passage 9 Tank remains full of developer for a timed interval and then valve 81 is opened to allow the developer to drain off and valve 86 is opened to allow rinse water to flow to the tank 65. Valve 81 may be closed to allow tank 65 to fill and then opened to allow it to drain when valve 86 is closed.

Valve 81 is then closed and valve is opened to allow a measured amount of fixer to flow from the tank to tank 65. When valve 81 is closed, tank 90 is refilled from its supply tank 88. After a timed interval, valve 81 is opened to allow the fixer to drain and valve 86 is again opened to rinse tank 65.

After the timed intervals for exposing the films 76 to the developer and the fixer and subsequent rinsing, the films are raised again past the rollers 70 to the position shown in FIG. 7, by turning arm 17 in the reverse direction, and a fan 96 (FIGS. 2 and 7) is turned on, the fan being arranged to blow warm air on the films to dry them.

When the films have dried, cover 12 is again raised, arm 15 is turned in the reverse direction to turn the card 55 upward, arm 14 is rotated reversely to release the wrapper flaps 30, and arm 16 is rotated reversely to advance the extractor slide 25. Wrappers 27 may then be removed and card 55, with films attached is removed from the carrier 20.

As seen in FIG. 12, a film cover 97 is provided for the card 55. The cover 97 may be folded on the line 98 and its two halves are provided with registering windows or openings 99 so that the main portion of the films may be viewed therethrough. The lower portions of the two halves of cover 97 are secured by staples, or otherwise, to the top portion of card 55 so that the identification data on the card 55 is not covered.

It will be seen that there has been provided a machine which provides for developing a plurality of dental films in one run without recourse to a darkroom.

It will be apparent that the valves 81, 84, 85 and 86 may be electrically operated valves and a float operated switch may be installed at the top of tank 65, as shown in phantom lines at 100 in FIG. 10. Switch 100 may be used to signal or to shut off the valves 84, 85 and 86 when tank 65 is full.

It will also be apparent that syringe-type injector cylinders may be used instead of the valves 84, 85 and 86 if the gravity flow of fluids is not desired. Motor means may be provided for rotating arms 14, 15, 16 and 17 and either electric programming means or fluidic programming means may be provided for operating the machine 10 except for the loading and unloading ofthe machine.

I claim:

1. A machine for developing dental radiographic films, the films having a lightproof wrapper extending around the film and terminating in a flap folded over an edge thereof and adapted to leave a portion of the film uncovered when unfolded, comprising: a lightproof housing having an access door, a film carrier rotatably mounted on a shaft transverse the machine, the carrier having a portion adapted to receive an identification card secured therein, the card having an edge portion coated with a gummy adhesive, a wrapper holding slide having a slanted edge, the slide being adapted to receive and hold a plurality of films with their wrappers, the wrapper flaps extending over the slanted edge, a flap opening rod carried on pulleys at either side of the slide, the rod normally lying in a groove in the slanted edge and adapted to be carried by the pulleys around the slanted edge for unfolding the wrapper flaps, means operable from outside the housing for rotating the rod carrying pulleys, means operable from outside the housing for rotating the carrier shaft for turning the adhesive coated card edge portions against the uncovered portions of the films, means operable from outside the housing for drawing the slide away from the carrier and separating'the wrappers from the films, the carrier rotating means being adapted to carry the films adhering to the card to a pendant position,

developing tank means below the carrier, means operable from outside the housing for moving the card holding portion of the carrier down until the films enter the developing tank means, the card holding portion of the carrier being spring biased upwardly, supply tanks for the developer and fixer, a source of heated water, and conduit and valve means in the housing operable from outside the housing for successively supplying and then allowing to drain away developer, fixer and water in the developing tank means for developing the films.

2. A machine for developing dental radiographic films as defined in claim 1, wherein the film carrier comprises a slideway member keyed to the shaft at either side of the carrier, a plate member slideable in p the slideway members, and two card holding bars spaced to form a card holding slot therebetween, the plate member being spring-biased to a stopped position in which the carrier shaft extends substantially along its midportion, the card holding bars having spring members engageable with a card in the slot and being spring-biased to a stopped position adjacent the carrier shaft, one of the bars having pin means at each end engageable with the means for moving the card holding portion of the carrier down when the carrier has been rotated to carry the films adhering to the card to apendant position.

3. In a machine for developing dental radiographic films, the combination of a lightproof housing having a door for access thereto, the films having lightproof wrappers extending around each film and terminating in a flap folded over an edge of the film and adapted to leave a portion of the film uncovered when unfolded, a slide in the housing having wrapper holding means thereon adapted to secure the wrappers on a plate with the wrapper flaps folded over an edge of the slide, whereby films and their wrappers may be manually placed in the wrapper holding means with the wrapper flap opened from the wrapper and spaced therefrom without exposing the films to light, the slide having a pulley rotatably mounted at either end, a rod having its ends carried by the pulleys, the rod normally lying in a groove extending along the edge over which the flaps are folded, the rod being adapted to becarried by the pulleys around the slide edge for opening the flaps to uncover a portion of each film when the access door is closed, means operable from outside the housing for rotating the pulleys, a film carrier rotatable from outside the housing and having portions covered with gummy adhesive adapted when the carrier is turned to contact the uncovered portion of the films, and means operable from outside the housing for moving the slide away from the carrier, whereby the wrappers are removed from the films and the films are secured to the film carrier.

4. The machine defined in claim 3 wherein developing tank means are secured in the housing below the film carrier, the adhesive covered portion of the carrier being telescopically extensible, means operable from outside the housing for extending the adhesive portion downward when the carrier with films attached is turned so that the films are pendant therefrom, whereby the films are carried into the developing tank means, supply tanks for developer and fixer solutions and a supply of heated water in the housing, conduit means connecting the supply tanks and water supply to the developing tank means, and valve means in the conduit means operable from outside the housing for successively supplying and then allowing to drain away developer, fixer and water to the developing tank means, the developing tank means being minimally larger than the films therein, whereby minimal amounts of developer and fixer may be used in developing the films and may then be economically disposed of without reuse.

5. A machine for developing dental radio'graphic films having lightproof wrappers comprising: a lightproof housing having an access door, means for securing the films in their wrappers in the housing, means operable from outside the housing after the door is closed for removing the films from their wrappers, the removing means including a film carrier, developing tank means in the housing below the carrier, the carrier having means operable from outside the housing for lowering the films into the developing tank means, supply tanks for developer and fixer solutions and a supply of heated water in the housing, conduit means connecting the supply tanks and water supply to the developing tank means, and valve means in the conduit means operable from outside the housing for successively supplying and then allowing to drain away developer, fixer and water in the developing tank means, a smaller tank under each of the supply tanks, a plate having a serpentine passage connected to the hot water source under the smaller tanks, a single conduit for supplying fluid to the developing tank means, a drain conduit leading from the developing tank means, a shutoff valve in the drain conduit, a shutoff valve between the serpentine passage and the single conduit for supplying rinse water to the developing tank means, the heated water flowing through the serpentine passage being adapted to heat the solution in the small tanks, and a supply valve between each of the small tanks and the single conduit, each supply valve being arranged to have an on position connecting its small tank and the single conduit and an off position connecting its supply tank to the smaller tank, each of the small tanks being vented to atmosphere and being of such size as to precisely fill the developing tank means, whereby a measured supply of heated solution is allowed to flow through the single conduit when the drain valve is closed and the supply valve is open, and the developing tank means is emptied and each small tank is filled from its supply tank when the drain valve is opened and the supply valve is closed. 

1. A machine for developing dental radiographic films, the films having a lightproof wrapper extending around the film and terminating in a flap folded over an edge thereof and adapted to leave a portion of the film uncovered when unfolded, comprising: a lightproof housing having an access door, a film carrier rotatably mounted on a shaft transverse the machine, the carrier having a portion adapted to receive an identification card secured therein, the card having an edge portion coated with a gummy adhesive, a wrapper holding slide having a slanted edge, the slide being adapted to receive and hold a plurality of films with their wrappers, the wrapper flaps extending over the slanted edge, a flap opening rod carried on pulleys at either side of the slide, the rod normally lying in a groove in the slanted edge and adapted to be carried by the pulleys around the slanted edge for unfolding the wrapper flaps, means operable from outside the housing for rotating the rod carrying pulleys, means operable from outside the housing for rotating the carrier shaft for turning the adhesive coated card edge portions against the uncovered portions of the films, means operable from outside the housing for drawing the slide away from the carrier and separating the wrappers from the films, the carrier rotating means being adapted to carry the films adhering to the card to a pendant position, developing tank means below the carrier, means operable from outside the housing for moving the card holding portion of the carrier down until the films enter the developing tank means, the card holding portion of the carrier being spring biased upwardly, supply tanks for the developer and fixer, a source of heated water, and conduit and valve means in the housing operable from outside the housing for successively supplying and then allowing to drain away developer, fixer and water in the developing tank means for developing the films.
 2. A machine for developing dental radiographic films as defined in claim 1, wherein the film carrier comprises a slideway member keyed to the shaft at either side of the carrier, a plate member slideable in the slideway members, and two card holding bars spaced to form a card holding slot therebetween, the plate member being spring-biased to a stopped position in which the carrier shaft extends substantially along its midportion, the card holding bars having spring members engageable with a card in the slot and being spring-biased to a stopped position adjacent the carrier shaft, one of the bars having pin means at each end engageable with the means for moving the card holding portion of the carrier down when the carrier has been rotated to carry the films adhering to the card to a pendant position.
 3. In a machine for developing dental radiographic films, the combination of a lightproof housing having a door for access thereto, the films having lightproof wrappers extending around each film and terminating in a flap folded over an edge of the film and adapted to leave a portion of the film uncovered when unfolded, a slide in the housing having wrapper holding means thereon adapted to secure the wrappers on a plate with the wrapper flaps folded over an edge of the slide, whereby filmS and their wrappers may be manually placed in the wrapper holding means with the wrapper flap opened from the wrapper and spaced therefrom without exposing the films to light, the slide having a pulley rotatably mounted at either end, a rod having its ends carried by the pulleys, the rod normally lying in a groove extending along the edge over which the flaps are folded, the rod being adapted to be carried by the pulleys around the slide edge for opening the flaps to uncover a portion of each film when the access door is closed, means operable from outside the housing for rotating the pulleys, a film carrier rotatable from outside the housing and having portions covered with gummy adhesive adapted when the carrier is turned to contact the uncovered portion of the films, and means operable from outside the housing for moving the slide away from the carrier, whereby the wrappers are removed from the films and the films are secured to the film carrier.
 4. The machine defined in claim 3 wherein developing tank means are secured in the housing below the film carrier, the adhesive covered portion of the carrier being telescopically extensible, means operable from outside the housing for extending the adhesive portion downward when the carrier with films attached is turned so that the films are pendant therefrom, whereby the films are carried into the developing tank means, supply tanks for developer and fixer solutions and a supply of heated water in the housing, conduit means connecting the supply tanks and water supply to the developing tank means, and valve means in the conduit means operable from outside the housing for successively supplying and then allowing to drain away developer, fixer and water to the developing tank means, the developing tank means being minimally larger than the films therein, whereby minimal amounts of developer and fixer may be used in developing the films and may then be economically disposed of without reuse.
 5. A machine for developing dental radiographic films having lightproof wrappers comprising: a lightproof housing having an access door, means for securing the films in their wrappers in the housing, means operable from outside the housing after the door is closed for removing the films from their wrappers, the removing means including a film carrier, developing tank means in the housing below the carrier, the carrier having means operable from outside the housing for lowering the films into the developing tank means, supply tanks for developer and fixer solutions and a supply of heated water in the housing, conduit means connecting the supply tanks and water supply to the developing tank means, and valve means in the conduit means operable from outside the housing for successively supplying and then allowing to drain away developer, fixer and water in the developing tank means, a smaller tank under each of the supply tanks, a plate having a serpentine passage connected to the hot water source under the smaller tanks, a single conduit for supplying fluid to the developing tank means, a drain conduit leading from the developing tank means, a shutoff valve in the drain conduit, a shutoff valve between the serpentine passage and the single conduit for supplying rinse water to the developing tank means, the heated water flowing through the serpentine passage being adapted to heat the solution in the small tanks, and a supply valve between each of the small tanks and the single conduit, each supply valve being arranged to have an on position connecting its small tank and the single conduit and an off position connecting its supply tank to the smaller tank, each of the small tanks being vented to atmosphere and being of such size as to precisely fill the developing tank means, whereby a measured supply of heated solution is allowed to flow through the single conduit when the drain valve is closed and the supply valve is open, and the developing tank means is emptied and each small tank is filled from its supply tank when the drain valve is opened anD the supply valve is closed. 